1. Field of the Invention
The present invention relates to a novel and unique strain of bacteria identified as Paenibacillus alvei strain TS-15 and its use and/or the use of any mutants thereof in controlling and/or eliminating the contamination of plant-based foods by pathogenic organisms, including especially Salmonella, that may cause disease or illness in plants or animals.
2. Background
Prevention of food-related illnesses (or foodborne illnesses) by microbial contamination is a major concern to the food industry, regulatory agencies, and consumers all around the world. Foodborne illnesses rank among the most serious of public health concerns and can be caused by any number of types of pathogens, including, for example, bacteria, viruses, parasites, and prions, as well as toxins produced by such pathogens. The Centers for Disease Control and Prevention (CDC) estimates that, in the U.S. each year, 76 million people become sick, more than 325,000 people are hospitalized, and 5,000 people die from foodborne illnesses. The estimated total cost of such illnesses weighs in the range of $10-83 billion each year, which accounts for medical expenses, reduced productivity and overall pain and suffering, among other costs.
A range of foods are associated with foodborne illnesses, including fresh produce. Produce is recognized as an important component of a healthy diet because it is a staple source of vitamins, minerals, fiber, and antioxidants. Produce can play an important role in weight management as well. Because most produce is grown in a natural environment, it is vulnerable to contamination with pathogens. Factors that may affect the rate of such contamination include agricultural water quality, the use of manure as fertilizer, the presence of animals in fields or packing areas, and the health and hygiene of workers handling the produce during production, packing, or preparation. The fact that produce is often consumed raw without any type of intervention to control or eliminate pathogens prior to consumption contributes to its potential as a source of foodborne illness.
The CDC estimates that, in the 1990's, at least 12 percent of foodborne illnesses were linked to fresh produce items. Over the past decade, the federal government has focused significant resources on reducing foodborne illness from all sources. However, despite these efforts, foodborne illness associated with fresh produce continues to be documented. The persistence of foodborne illness associated with fresh produce may be attributable to a number of factors, but many cases are preventable. Given the importance of produce consumption and its central role in a healthy diet, it is imperative that the number of foodborne illness cases associated with produce be reduced.
Many incidents of produce-related foodborne illness relate to salmonellosis, which can be caused by ingestion of fresh produce, plants, fruits or vegetables, or other produce-related products which are contaminated with or contain various nontyphoidal species of Salmonella bacteria. Salmonella infections cause fever and gastrointestinal-related symptoms, including diarrhea, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts 4 to 7 days and most people recover without treatment. However, in some the diarrhea may be so severe that the patient becomes dangerously dehydrated and requires hospitalization. Treatment may include intravenous fluids to combat the dehydration, and medications, including antibiotics and anti-fever medications, may be given to provide symptomatic relief and/or to eliminate the infection. In severe cases, the Salmonella infection may spread from the intestines to the blood, and then to other body sites, and can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to develop severe illness. Some people afflicted with salmonellosis later experience reactive arthritis, which can have long-lasting, disabling effects.
Contamination of produce, such as tomatoes, by pathogens like Salmonella can occur practically at any point in the produce supply chain, i.e., at any point between the farm and the market. Vulnerable points in the supply chain can include prior to, during or after planting, during open field or greenhouse production, harvesting, field packing or packinghouse, distribution operations, retail food sales, and foodservice sales and preparations. In addition, the soil itself may already be contaminated with the organisms prior to utilizing the land. For example, the soil may be the target of run-off from farm-related animal waste that is contaminated with Salmonella. 
Produce crops—besides providing a vehicle for certain human or animal pathogens—also may often suffer significantly from a wide variety of plant diseases, the occurrence of which may cause a marked decrease in crop yields, produce quality and appearance, and overall value. Depending on the particular crop, diseases can be caused by any number of different types of plant pathogens, including those that are bacteria, viruses, fungi or other parasites.
As a means for controlling both plant and human/animal pathogens, there have been a wide array of strategies previously implemented or which continue to be used. Some of these strategies generally relate to the control of the cultivation environment, the use of disease-resistant cultivars, the application of agricultural and horticultural fungicides or bactericides, and the biological control of the diseases by the use of organic materials or the like. Of these, the use of agricultural and horticultural fungicides or bactericides or other anti-pathogen agents is direct and often the most effective. However, the application of a large amount of the fungicides or bactericides is clearly undesirable because of the resultant harmful effects on the environment and wildlife that comes into contact with the treated region or with products thereof. In addition, a plurality of fungicidal and/or bactericidal chemicals are often employed to combat the potential for resistance, thereby increasing the level of such chemicals and their negative effects on the environment.
In order to solve the problem of excessive dependence on the use of such harmful agrochemicals, methods for controlling various crop plant diseases and/or human/animal pathogens that contaminate such crop plants have been developed which employ the use of microbial biocontrol agents. Such microorganisms may be natural enemies of the target pathogens sought to be controlled or eradicated, or may be modified genetically to be capable of mitigating or even eliminating unwanted plant and/or human or animal pathogens on crop plants. However, the efficacy of such agents are not yet sufficient. Challenges presented in developing an effective microbial biocontrol agent can include, for example, poor survivability once placed into contact with the crops or the produce itself and low effectiveness of an agent's anti-pathogen activity. Additionally, it is mostly the case that microbial biocontrol agents have been developed for the control of plant-based pathogens, rather than the control of human or animal pathogens associated with plants.
Accordingly, improved microbial biocontrol agents which are more effective against pathogens, have greater sustainability once released into the environment without being harmful to humans, and which are simultaneously effective against both plant and human/animal pathogens would be highly desirable in the art.